Previous research indicates that lesbian, gay, bisexual and transgender (LGBT) adults experience more adverse health outcomes than their peers. Findings from the few studies examining weight disparities among adults suggest that lesbian women are more likely to be overweight or obese compared to their heterosexual peers, though less is known about gay men and bisexuals. Given the scant research to date in this area, the Institute of Medicine (IOM) recently issued a call for additional research on LGBT health. Furthermore, IOM highlighted the need to utilize a life-course framework when examining health disparities by sexual identity, acknowledging the unique influence of various life stages on health. Emerging adulthood (i.e., ages 18-25) is an important age at which health disparities emerge, and an age characterized by adverse changes in weight, dietary quality, and physical activity. Emerging adults experience vulnerabilities as they find independence and negotiate new responsibilities, life skills, and identities during the transition to adulthood. For LGBT youth, these transitions may be layered with many additional complexities. In that half of US high school graduates up to age 24 are enrolled in post-secondary education, post-secondary institutions may be important arenas for examining and addressing emerging adult health disparities, including those among LGBT groups. We have the unique opportunity here to analyze 2007-2011 state surveillance data of nearly 30,000 post-secondary students, including a large sub-sample of nearly 2,000 lesbian, gay, bisexual and questioning (LGB) young people, attending an array of 2- and 4-year colleges and universities. Our aims are to: (1) Quantify disparities in obesity, dietary intake, physical activity, unhealthy weight control behavior, body satisfaction and other weight-related health outcomes among LGB and heterosexual students; (2) Identify major weight-related health behavioral patterns, or profiles, and the extent to which these behavioral profiles differ by sexual identity and gender; and (3) Characterize these behavioral profiles by demographic factors and health outcomes (e.g., age, socioeconomic status, health care coverage, obesity, and health status). We hypothesize that LGB students engage in more adverse behaviors than their heterosexual peers and exhibit differential behavioral patterning. For example, based on previous research, we hypothesize that gay men are more likely to exhibit a pattern of unhealthy weight control and body dissatisfaction, whereas lesbians are more likely to engage in a pattern characterized by high physical activity coupled with higher alcohol and tobacco use and other adverse behaviors. Given the limited understanding of LGB weight-related health, particularly emerging adults, this study will fill important gaps in the literature identified by IOM and others. Furthermore, the findings from this R21 will serve as critical formative research needed to inform an R01 that will tailor and test an LGB-specific obesity intervention.